AGRItf  DEPT, 


STATE  HORTICULTURAL  COMMISSION 

ELLWOOD  COOPER,  Commissioner 


THE  RUSSIAN  THISTLE 


ITS  INTRODUCTION  AND  SPREAD 


IN  CALIFORNIA,  WITH  LAWS  AND 


MEASURES    FOR     ITS    CONTROL 


WITH    A    DESCRIPTION    OF    THE    CANADA    AND 
SCOTCH    THISTLES 


SACRAMENTO 

w.  \v.  SHANNON,       :     :     :     :     :       SUPERINTENDENT  STATE  PRINTING 

1905 


STATE  HORTICULTURAL  COMMISSION 

ELLWOOD  COOPER,  Commissioner 


THE  RUSSIAN  THISTLE 


ITS  INTRODUCTION  AND  SPREAD 


IN  CALIFORNIA,  WITH  LAWS  AND 


MEASURES    FOR     ITS    CONTROL 


WITH    A    DESCRIPTION    OF    THE    CANADA   AND 
SCOTCH    THISTLES 


SACRAMENTO 

w.  w.  SHANNON,      :     :     :     :     :      SUPERINTENDENT  STATE  PRINTING 

1905 


AGRIC.  DEPT. 
CALIFORNIA  5TATL  COMMISSION  OF  HORTICULTURE.. 


» 
ELLWOOD  COOPER Commissioner Santa  Barbara. 

JOHN  ISAAC Secretary San  Francisco. 

ED.  M.  EHRHORN  _.  Deputy Mountain  View. 

E.  K.  CARNES Assistant  Deputy Riverside. 

O.  E.  BREMNER Second  Assistant Santa  Rosa. 

GERTRUDE  BIRD...  Stenographer Sacramento. 


OFFICE: 

ROOM  41,   STATE  CAPITOL,  SACRAMENTO. 
BRANCH  OFFICE,  ROOM  11,  FERRY  BUILDING,  SAN  FRANCISCO. 


•     '     "  / 


THE  RU55IAN  THI5TLL 


Description,  and  Measures  for  Its  Control. 


. 
The  Legislature  of  California,  at  its  thirty-sixth  session,  passed  an 

\vhieh  was  approved  by  the  Governor  on  March  20,  1905,  increasing 

the  duties  of  the  Horticultural  Commissioners  and  local  inspectors  of  the 

di tit-rent  counties  by  providing  that  they  should  be  required  to  "super- 

i  he  destruction  of  scale  insects,  diseases,  Russian  thistle  or  salt- wort, 

or  other  noxious  weeds. ' ' 

This  law,  under  the  statutes,  went  into  effect  sixty  days  from  date  of 
signing,  which  was  on  May  20th.  Since  the  imposition  of  these  new 
duties  upon  the  horticultural  officers  of  the  State,  there  have  been 
numerous  inquiries  at  this  office  as  to  how  the  Russian  thistle  may  be 
recognized  and  what  are  to  be  considered  as  noxious  weeds.  The  ques- 
tion of  what  shall  be  considered  * '  noxious  weeds, ' '  we  suppose,  will  have 
to  be  left  largely  to  the  County  Boards  of  Horticulture  and  the  Boards 
of  Supervisors,  for  weeds  that  are  exceedingly  noxious  in  some  portions 
of  the  State  can  hardly  be  considered  so  in  others;  but  in  the  matter 
of  new  weeds  there  can  be  no  doubt,  and  this  is  particularly  true  of  the 
Russian,  the  Canada,  and  the  Scotch  thistles,  and  especially  so  of  the 
former,  which  has  already  obtained  a  foothold  in  several  of  our  counties, 
but  which  has  not  as  yet  become  so  firmly  established  as  to  be  beyond 
possibility  of  extirpation. 

From  the  fact  that  the  Russian  thistle  is  a  new  weed  in  our  State, 
there  exists  a  vast  amount  of  ignorance  concerning  it.  Owing  to  its 
name,  which  is  an  absurd  misnomer,  every  species  of  thistle  and  many 
other  weeds  are  mistaken  for  it,  and  from  various  sources  we  learn  of 
its  existence  over  the  length  and  breadth  of  the  State,  but  in  most  cases 
our  informants  are  mistaken. 

The  fact  is,  that,  at  present,  this  pest  is  confined  to  so  limited  an  area 
in  California  that  it  may  be  said  not  to  exist  here,  and  it  is  in  order 
that  our  Horticultural  Commissioners  and  local  inspectors  and  others 
interested  may  be  able  to  recognize  this  weed  on  sight,  and  also  to 
realize  the  great  importance  of  totally  eradicating  it  where  it  may  be 
discovered,  that  this  bulletin  is  published.  The  necessity  of  this  is 
forced  upon  us  by  the  fact  that,  since  the  law  became  operative  very 

337205 


4  THE  'RUSSIAN    THISTLE. 

many  oi'  onr  Horticultural  Commissioners,  anxious  to  do  their  duty 
under  its  provisions,  have  sent  to  this  office  specimens  of  various  weeds 
under  the  impression  that  they  were  the  Russian  thistle,  but  in  no  case 
has  this  supposition  been  correct. 

In  the  first  place,  it  should  be  understood  that  the  '  *  Russian  thistle ' ' 
is  not  a  thistle  at  all.  It  does  not  belong  to  the  thistle  family ;  in  fact, 
does  not  resemble  a  thistle  in  any  respect— in  its  habits  of  growth, 
foliage,  inflorescence,  seeds,  or  methods  of  distribution.  It  is  as  much 
like  a  cabbage  as  it  is  like  a  thistle,  and  how  it  got  its  name  is  a  mystery. 
It  may  be  that,  as  the  uninformed  in  California  call  all  plants  with 
thorns  cactuses,  so  the  Dakota  farmers,  when  they  saw  that  the  plant 
had  prickles,  concluded  that  all  prickly  plants  must  be  thistles,  and  so 
gave  it  this  name;  but  if  our  readers  want  to  recognize  the  "Russian 
thistle,"  they  must  not  look  for  a  thistle.  In  its  native  land  this  weed 
is  called  "  Leap-the-field, "  which  is  certainly  more  descriptive,  and  the 
German  colonists  in  Russia  call  it  "wind  witch."  Either  of  these- 
names  is  more  suitable  than  that  of  thistle. 

The  Russian  thistle  is  a  tumbleweed  and  is  somewhat  related  to  our 
American  tumbleweed  (Amaranthus  albus),  which,  in  its  turn,  is  near 
to  our  common  pigweed  or  red-root  (Amaranthus  sp.).  Its  scientific 
name  is  Salsola  kali  var.  tragus.  It  is  an  annual,  coming  from  seed  each 
year,  and  in  California  makes  its  appearance  in  March  and  April.  The 
first  leaves  are  two  small  tender  shoots,  about  an  inch  in  length,  some- 
what resembling  grass  blades.  Between  these  seed  leaves  the  true  stem 
soon  makes  its  appearance.  This  is  lined  with  sharp-pointed,  slender 
leaves,  from  the  axils  of  which  branches  are  soon  thrown  out.  Its  growth 
during  the  early  stages  is  rather  slow,  and  the  plant,  being  then  young 
and  tender,  is  eaten  by  stock;  horses,  cattle,  and  sheep  devouring  it 
eagerly.  When  about  two  months  old  the  plant  begins  to  blossom:  it 
loses  its  tenderness,  the  stem  becomes  dry  and  rigid,  with  reddish 
stripes,  the  spines  on  the  leaves  become  hard,  and  the  true  leaves  fall 
off.  The  flowers  are  very  small,  of  a  greenish  color,  and  inconspicuous, 
each  borne  in  the  axil  of  a  leaf  and  surrounded  by  three  small,  spiny 
bracts.  Although  the  flowers  are  borne  separately  upon  the  stem,  they 
appear  in  multitudes  on  the  plant,  and  each  produces  its  seed. 

As  the  plant  increases  in  age  it  also  increases  greatly  in  size,  until  it 
forms  a  dense,  bushy  mass  of  spiny  branches,  frequently  from  2  to  3  feet 
in  height  and  from  4  to  6  feet  in  diameter.  Each  of  these  branches  is 
lined  its  entire  length  with  seeds,  and  it  has  been  estimated  that  a  single 
plant  of  average  size,  from  2  to  3  feet  in  diameter,  and  weighing  from 
2  to  3  pounds,  at  maturity,  when  dry,  will  bear  from  20,000  to  30,000 
seeds,  while  there  have  been  found  single  plants  weighing  20  pounds, 
with  a  diameter  of  6  feet,  which,  it  was  estimated,  would  yield  200,000 
seeds. 


THE    RUSSIAN    THISTLE. 

The  whole  plant  is  horn.'  upon  a  single,  short,  slender  stem,  half  an 
inch  or  less  in  dimmer,  which,  when  the  plant  ripens,  dries  and  becomes 
very  brittle.    Under  pressure  of  the  first  hard  wind,  it  snaps  off,  and  the 
«l  goes  bounding  along  before  the  wind,  distributing  the  seeds  in 
y  direction.     In  Dakota,  specimens  which  had  been  tagged  were 
traced  for  a  distance  of  from  10  to  15  miles,  so  it  will  be  readily  under- 
stood that  a  single  plant  may  be  the  cause  of  infesting  a  very  large  area 
of  territory  in  a  few  seasons,  and  the  necessity  of  extirpating  every 
specimen  on  sight  will  be  appreciated. 

The  seed  is  described  as  quite  small,  of  rather  peculiar  shape,  and  the 
whole  space  inside  the  coat  is  occupied  by  the  embryo  or  young  plant, 
there  being  no  albumen,  as  is  the  common  condition  in  the  grains. 
After  the  plant  is  mature,  the  branches  lose  their  red  and  green  color 
and  become  dry  and  bleached  in  appearance.  The  root,  which  is  at  no 
time  very  well  developed,  then  breaks  off  near  the  surface  and  the 
plant  is  ready  to  start  on  its  seed-scattering  journey  before  the  wind. 
And  it  is  well  suited  to  this  mode  of  transportation.  It  is  light,  wiry, 
and  strong;  its  shape  is  pretty  nearly  that  of  a  sphere,  and  it  goes 
bounding  across  fields  until  it  is  stopped  by  a  fence  or  a  ditch  or  vegeta- 
tion, leaving  its  seeds  scattered  over  miles  of  surface,  ready  to  sprout 
as  soon  as  favorable  conditions  shall  arise. 

The  following  technical  description  is  taken  from  Bulletin  No.  15, 
Division  of  Botany,  U.  S.  Department  of  Agriculture,  by  L.  H.  Dewey : 

~s,,ls<>1.,  l-nli  tragus  (L.)  Moq.  in  D.  C.  Prod.,  XIII,  2,  187  (1849). 
A  herbaceous  annual,  diffusely  branching  from  the  base,  1%  to  3  feet 
(0.5  to  1  m.)  high  and  twice  as  broad,  smooth  or  slightly  puberulent; 
tap  root  dull  white,  slightly  twisted  near  the  crown;  leaves  alternate, 
sessile;  those  of  the  young  plant  deciduous,  succulent,  linear  or  sub- 
terete,  1  to  2  inches  (3  to  6  cm.)  long,  spine-pointed,  with  narrow, 
denticulate,  membranaceous  margins  near  the  base ;  leaves  of  the  mature 
plant  persistent,  each  subtending  two  leaf-like  bracts  and  a  flower  at 
intervals  of  one  twelfth  to  five  twelfths  of  an  inch  (2  to  10  mm.),  rigid, 
narrowly  ovate,  often  denticulate  near  the  base,  spine-pointed,  usually 
striped  with  red  like  the  branches,  three  twelfths  to  five  twelfths  of  an 
inch  (6  to  10  mm.)  long;  bracts  divergent,  like  the  leaves  of  the  mature 
plant  in  size  and  form;  flowers  solitary  and  sessile,  perfect,  apetalous, 
about  five  twelfths  of  an  inch  ( 10  mm. )  in  diameter ;  calyx  membrana- 
ceous, persistent,  inclosing  the  depressed  fruit,  usually  rose-colored, 
gamosepalous,  cleft  nearly  to  the  base  into  five  unequal  divisions,  about 
one  sixth  of  an  inch  (4  mm.)  long,  the  upper  one  broadest,  bearing  on 
each  margin  near  the  base  a  minute  tuft  of  very  slender  coiled  hairs,  the 
two  nearest  the  subtending  leaf  next  in  size,  and  the  lateral  ones  narrow, 
each  with  a  beak-like  connivent  apex,  and  bearing  midway  on  the  back 
a  membranaceous,  striate,  erose-margined  horizontal  wing  one  twelfth 


6  THE    RUSSIAN   THISTLE. 

of  an  inch  (2  mm.)  long,  the  upper  and  two  lower  wings  much  broader 
than  the  lateral  ones;  stamens  five,  about  equaling  the  calyx  lobes; 
pistil  simple;  styles  two,  slender,  about  one  twenty-fifth  of  an  inch 
(1  mm.)  long;  seed  one,  obconical,  depressed,  one  sixteenth  of  an  inch 
(nearly  2  mm.)  in  diameter,  dull  gray  or  green,  exalbuminous,  the  thin 
seed-coat  closely  covering  the  spirally  coiled  embryo;  embryo  green, 
slender,  about  one  half  inch  (12  mm.)  long  when  uncoiled,  with  two 
linear  cotyledons.  The  plant  flowers  in  July  or  August,  and  the  seeds 
mature  in  September  and  October.  At  maturity,  the  action  of  the  wind 
causes  the  root  to  break  with  a  somewhat  spiral  fracture  at  the  surface 
of  the  frozen  ground,  and  the  plant  is  blown  about  as  a  tumbleweed. 
The  mature  flower  with  the  inclosed  seed  is  held  in  place  by  the  minute 
tufts  of  coiled  hairs,  preventing  the  seeds  from  falling  all  at  once  when 
the  plant  begins  to  roll." 

This  plant  is  especially  well  adapted  to  California  conditions,  and 
should  it  once  obtain  a  foothold  here  would  prove  the  most  serious  of 
any  of  our  imported  weed-pests.  It  is  well  adapted  to  our  arid  con- 
ditions, maturing  its  seed  early  in  the  season,  in  readiness  for  the  first 
north  wind  to  start  it  on  its  journey  of  seed-distribution.  The  plant 
is  a  native  of  eastern  Europe  or  western  Asia,  where  it  is  as  unfavorably 
known  as  it  is  now  in  the  Dakotas.  It  was  first  introduced  in  the 
Dakotas  in  Bonhomme  County,  in  flax  seed  imported  from  Europe  in 
1873.  In  a  few  years  it  increased  with  terrible  and  destructive  rapidity, 
until  in  1892,  Mr.  Dewey,  Assistant  Botanist  of  the  U.  S.  Department  of 
Agriculture,  estimated  that  the  cost  to  the  farmers  of  Dakota  alone  in 
loss  of  crops  was  over  $2,000,000  for  that  season.  In  1893  this  estimate 
was  increased  for  the  West  to  from  $3,000,000  to  $5,000,000,  and  this 
has  since  been  largely  augmented  by  the  greatly  increased  area  subju- 
gated by  the  pest. 

From  a  circular  of  Prof.  L.  H.  Dewey,  Assistant  Botanist  of  the  U.  S. 
Department  of  Agriculture,  treating  on  the  Russian  thistle,  we  take  the 
following : 

"The  injury  to  crops  is  of  course  the  most  important  item  in  the 
damage  caused  by  the  Russian  thistle.  It  takes  complete  possession  of 
the  land,  crowding  out  other  plants.  Flax,  wheat,  rye,  barley,  and  oats 
all  suffer  from  its  effects,  not  only  in  the  reduction  of  the  crop  but  in 
the  lower  grade  of  that  which  is  harvested.  Corn,  potatoes,  vegetables, 
and,  in  fact,  nearly  all  cultivated  crops  are  injured  more  or  less,  pro- 
portionately to  their  lack  of  care  and  cultivation. 

"The  spiny  character,  added  to  the  rigid,  bushy  habit  of  the  plant, 
makes  it  one  of  the  most  disagreeable  of  weeds  to  handle.  When 
mature  it  can  not  be  plowed  under,  and  it  is  often  impossible  to  plow 
fields  at  all  until  the  thistles  are  removed.  Binders  can  not  be  run 
where  the  thistles  are  abundant,  and  even  the  working  of  the  headers 


8  THE    RUSSIAN    THISTLE. 

is  seriously  interfered  with.  The  annoyance  and  positive  injury  to  men 
and  animals  which  they  cause  by  their  rigid  spines  is  undoubtedly 
greater  than  that  caused  by  any  of  the  true  thistles.  A  trouble  of 
another  kind  results  from  their  being  blown  during  prairie  fires  across 
fire  breaks  that  would  otherwise  be  ample  protection  to  stacks  or 
buildings. 

"Warning  to  Pacific  Coast  Wheat-growers.— ^&$\,  of  the  Rocky 
Mountains  the  thistle  is  already  so  widely  distributed  that  its  continued 
progress  in  that  region  is  inevitable.  Its  advent  in  Idaho  and  California, 
however,  is  a  far  more  serious  matter.  The  Rocky  Mountains  present  a 
great  natural  barrier  which  the  thistle  will  not  easily  pass,  except  by 
artificial  conveyance.  With  the  natural  conditions  thus  favorable  to  its 
exclusion,  and  with  a  full  knowledge  of  the  disastrous  nature  of  the 
scourge,  it  is  almost  criminal  to  allow  it  to  become  established  west  of 
the  Rockies.  To  the  Pacific  Coast  the  Sierra  Nevada  and  Cascade 
mountains  afford  additional  protection,  but  some  seed  will  be  sure  to 
find  its  way  over  this  barrier  also,  especially  if  the  thistle  is  allowed  to 
obtain  a  hold  in  the  Great  Basin.  In  view  of  these  facts,  the  California 
wheat-grower  should  take  precautions  against  the  weed,  opposing  both 
its  direct  introduction  into  California  from  the  plains  east  of  the  Rockies 
and  its  gradual  advance  by  way  of  the  Great  Basin. 


"The  plant  is  an  annual,  easily  killed  at  any  time  during  the  growing 
season.  It  produces  no  seed  before  the  middle  of  August  or  first  of 
September,  and  the  seed  is  short-lived.  The  circumstances,  therefore, 
are  exceptionally  favorable  for  its  being  checked,  or  even  exterminated. 
In  order  to  secure  a  complete  extirpation  these  two  conditions  must  be 
fulfilled: 

"1.  No  Russian  thistle  shall  be  allowed  to  produce  seed. 

"2.  There  must  be  concerted  action  throughout  all  the  infested  area. 

"If  the  Russian  thistle,  wherever  found,  should  be  killed  before  it 
produces  seed  during  three  successive  years,  the  pest  would  in  all 
probability  be  completely  exterminated;  for  the  experiments  already 
made  indicate  that  the  vitality  of  the  seed  is  lost  within  that  period. 
But  since  the  ground  is  so  easily  reseeded  from  a  neighboring  crop,  if 
action  is  not  taken  everywhere  and  at  one  time  the  work  will  have  to 
be  done  over  indefinitely. 

"In  the  absence  of  universal  concerted  action,  as  extensive  coopera- 
tion as  possible  should  be  secured ;  and  at  all  events  each  farmer  should 
protect  his  own  farm  as  well  as  he  may,  in  doing  which  he  will  also 
avoid  injuring  his  neighbor.  The  want  of  cooperation  is  a  great  dis- 
advantage. Farmers  in  some  instances  have  so  far  succeeded  in  keeping 


THE    RUSSIAN    THISTLE.  9 

the  weed  under  that  their  crops  have  been  little  injured,  but  it  has 
cost  a  great  deal  in  extra  labor,  and  they  have  been  compelled  to  fight 
it  every  year  h.-cause  of  -seed  blown  in  from  adjacent  lands.  On  the 
other  hand,  the  farmer  who  has  not  attempted  to  drive  the  weed  from 
his  farm  has  sustained  immense  damage  to  his  crops,  and  in  some  cases 
has  even  been  driven  from  his  farm. 

"Remuli'*  in  Cultivated  Fields.— Wheat  and  other  spring  crops 
should  be  sowed  as  early  as  possible  on  well-prepared  land,  so  that  the 
crop  may  get  a  vigorous  start  and  shade  the  ground  before  the  weed 
seeds  germinate.  The  wheat  may  then  be  cut  early,  when  there  is  less 
da  111:1  -r  that  the  thistle  plants  will  be  large  enough  to  cause  trouble  in 
harvesting.  By  such  a  plan  this  and  many  other  weeds  growing  in  the 
stubble  may  be  destroyed  before  they  produce  seed. 

* '  The  land  should  be  plowed  as  soon  as  possible  after  the  wheat  is  cut, 
and  if  this  can  not  be  done  before  the  first  of  September  the  stubble 
should  be  burned.  The  thistle  is  still  rather  juicy  in  August  and  burns 
with  difficulty,  so  that  it  is  advisable  to  mow  the  stubble  and  let  it  dry 
a  few  days  before  firing.  In  this  connection  the  importance  of  harvest- 
ing with  a  header  is  to  be  emphasized,  as  the  greater  amount  of  stubble 
left  by  this  process  furnishes  material  for  a  more  thorough  burning. 
The  land  should  be  plowed  or  the  stubble  burned  immediately  after 
harvesting  a  crop  of  barley,  rye,  or  oats. 

"Crops  like  corn,  potatoes,  and^beets  should  be  kept  thoroughly  culti- 
vated as  late  as  possible.  The  extra  cultivation  will  produce  a  better 
crop  as  well  as  kill  the  weeds.  Several  cornfields  seen  in  the  fall  of 
1893  evidently  produced  a  much  better  crop  of  Russian  thistles  and 
pigeon  grass  than  of  corn,  while  other  fields  near  by,  apparently  with 
the  same  kind  of  soil,  but  free  from  pigeon  grass  and  the  Russian  thistle, 
bore  a  corn  crop  fifty  per  cent  better.  Such  crops  should  be  cultivated 
until  they  thoroughly  shade  the  ground,  and  if  thistles  appear  after 
that  the  hoe  should  be  used,  so  that  none  may  be  allowed  to  produce 
seed.  Potato  fields  and  gardens  devoted  to  early  crops  should  receive 
better  attention  than  heretofore.  When  cultivated  only  enough  to 
produce  a  crop  and  allowed  to  remain  unworked  after  the  middle  of 
July  these  places  usually  produce  an  enormous  number  of  large  thistle 
plants.  Many  such  fields  were  seen  during  the  autumns  of  1892  and 
1893  which  might  have  been  plowed  for  $5  or  less,  or  even  planted  with 
a  paying  second  crop,  but  instead  were  left  to  produce  a  crop  of  weeds, 
which  might  easily  cause  damage  to  the  extent  of  hundreds  of  dollars. 

"If  summer-fallowing  is  practiced,  the  land  should  be  plowed  late 

the  spring,  so  that  seeds  near  the  surface  will  have  germinated  and 
young  plants  be  killed.  The  harrow  or  cultivator  should  be  kept 

use  during  the  summer.    The  thorough  cultivation  will  improve  the 

idition  of  the  soil  for  future  crops  as  well  as  keep  the  weeds  from 


2.— Branch  from  Russian  thistle,  showing  appearance  of  plant  when  seeds  are 
mature;  a,  branch  from  a  young  plant,  showing  the  appearance  before 
the  dry  season;  b,  mature  seed,  enlarged  five  times.  (From  U.  S.  Dept.  oi 
Agriculture.) 


FMULLCA 


.  -Branch  of  Russian  thistle,  showing  appearance  before  flowering  and  before  the  spiny 

branchlets  have  elongated ;  a,  spines,  enlarged ;   b,  young  grain  with   the  covering 

removed,  enlarged  about  seven  times:  e,  lilosM.m  removed  from  the  axil  and  viewed 

from  below,  enlarged  about  four  times:  <l.  section  of  fruiting  calyx,  side  view;  e,  same, 

Q  fr««in  above.     (From  U.  S.  Dept.  of  Agriculture.) 


12  THE    RUSSIAN    THISTLE. 

seeding.  This  is  the  theory  of  summer-fallowing,  but,  unfortunately, 
it  has  seldom  been  fully  carried  out  in  the  Dakotas  and  adjoining 
States.  The  land  there  has  usually  been  left  untouched  after  the 
spring  plowing.  Instead  of  a  barren  fallow  or  'resting  period/  a  crop 
of  weeds  is  grown,  which  drains  the  land  almost  as  much  as  a  crop  of 
grain,  and  the  soil,  instead  of  being  cleared  of  weeds,  becomes  a  veri- 
table hotbed  of  them.  Summer-fallowing,  even  if  the  land  is  kept 
barren  by  cultivation,  gives  comparatively  little  benefit  except  to  clear 
out  the  weed  seed.  This  object  may  be  attained  just  as  well  by  raising 
a  crop  which  will  pay  the  expenses  of  cultivation.  Beans,  peas,  clover, 
millet,  or  rye  may  be  sown,  pastured,  and  plowed  under  for  green  fer- 
tilizer at  little  expense,  and  it  will  improve  the  land  vastly  more  than 
barren  fallowing.  Millet  and  oats  combined  may  be  grown  and  cut  for 
hay.  This  crop  will  choke  out  nearly  all  weeds,  while  the  few  that  do 
grow  will  be  slender  and  weak,  producing  comparatively  few  seeds,  and 
many  will  be  cut  with  the  hay  before  producing  any  seed. 

"Roadsides,  Fire  Breaks,  and  Waste  Places. — If  the  Russian  thistle  is 
to  be  kept  out  of  cultivated  fields  it  must  be  exterminated  on  roadsides, 
fire  breaks,  and  waste  land  where  the  sod  has  been  broken,  and  in  all 
places  where  it  has  obtained  foothold. 

* '  In  many  places  the  prairie  roads,  which  are  usually  mere  unf  enced 
driveways,  are  lined  on  each  side  by  hedges  of  robust  Russian  thistles 
growing  between  the  beaten  track  and  the  prairie  grass,  as  ragweeds 
grow  along  roads  in  the  East.  A  road  machine  may  here  be  used  to 
good  advantage,  the  scraper  being  so  set  as  to  take  as  thin  a  layer  of 
earth  as  possible,  and  weeds  and  all  being  thrown  to  the  middle  of  the 
track.  Fire  breaks  can  be  kept  free  from  the  Russian  thistle  and  other 
weeds  most  economically  by  frequent  use  of  the  harrow.  When  covered 
with  large  dry  tumbleweeds,  as  they  frequently  are,  instead  of  being 
a  protection  they  become  a  source  of  great  danger  in  times  of  prairie 
fires. 

"In  the  sand  hills,  on  public  lands,  and  in  the  scattered  weed  patches 
of  cattle  ranges  there  seems  to  be  no  direct  compensation  for  the  labor 
expended  in  exterminating  the  weeds.  The  thistles,  however,  must 
be  destroyed  in  these  places,  and  the  work  may  be  done  at  a  cost  small 
in  comparison  with  the  damage  these  plants  would  cause  if  allowed  to 
produce  seed. 

"The  great  windrows  of  Russian  thistles  found  banked  up  against 
wire  fences  in  early  winter  suggest  the  use  of  fences  to  check  the  dis- 
semination of  the  weed  by  rolling.  The  thistles,  however,  will  easily 
bound  over  a  fence,  especially  after  a  bank  reaches  its  top ;  and  at  any 
time  the  whole  pile  is  liable  by  a  shift  in  the  wind  to  be  sent  off  in  some 
other  direction.  Prompt  burning  would  be  of  some  value,  and  this 
would  be  possible  if  metallic  fence  posts  were  used. 


THE    RUSSIAN   THISTLE.  13 


"Like  all  noxious  weeds,  the  Russian  thistle  may  be  kept  out  much 
more  easily  than  it  can  be  eradicated  when  once  established.  In  regions 
not  yet  infested  all  avenues  of  introduction  should  be  watched  so  that 
it  may  be  discovered  and  killed  before  it  can  obtain  a  footing. 

'  *  It  may  be  expected  along  all  lines  of  railroads,  especially  those  hav- 
ing direct  traffic  with  infested  regions.  It  is  by  way  of  the  railroads  that 
the  seeds  most  often  enter  new  territory,  being  dropped  from  stock  or 
grain  cars  at  stock  yards,  elevators,  and  sidings.  The  plants  usually 
appear  first  close  along  the  tracks  by  the  ends  of  the  ties,  where  the 
seeds  falling  from  the  cars  find  conditions  favorable  to  growth  in  the 
unoccupied  soil,  kept  stirred  by  repairs  on  the  tracks  and  the  ballast. 

1 1  The  seeds  have  been  introduced  in  some  cases  in  baled  hay  and  grain 
at  fair  grounds,  race  tracks,  lumber  camps,  and  railroad  construction 
camps.  They  have  also  been  carried  in  shelled  corn,  wheat,  oats,  millet, 
flax,  alfalfa,  and  grass  seed.  They  are  supposed  to  have  been  brought 
to  some  localities  in  Idaho  in  sheep's  wool.  While  the  seed  has  no 
hooks,  barbs,  or  gum  to  cause  it  to  stick  like  cocklebur  or  clammy 
cuphea,  its  small  size  and  light  weight  enable  it  to  retain  a  place  for 
some  time  in  a  fleece. 

"Another  means  of  introduction  and  rapid  distribution,  and  one  that 
threatens  to  be  most  troublesome,  is  running  water.  During  the  past 
three  years  the  thistle  has  spread  with  remarkable  rapidity  over  irri- 
gated lands  in  Colorado  and  Idaho.  Robust  plants  are  produced  on 
the  banks  of  the  irrigating  canals  and  ditches.  The  seeds  from  these 
are  carried  long  distances  by  the  water  and  deposited  in  the  fields.  In 
some  cases  quarter-sections  of  irrigated  land  have  been  practically 
covered  with  the  Russian  thistle  in  a  single  season.  The  plants  have 
also  spread  along  river  banks,  especially  during  freshets. 

"These  sources  of  introduction  should  be  carefully  guarded,  and 
every  Russian  thistle  seen  should  be  destroyed  before  it  has  produced 
seed.  If  any  escape  notice  until  the  seeds  are  mature  they  should  be  cut 
and  burned  before  they  begin  to  roll.  One  Russian  thistle  destroyed 
this  year  is  likely  to  obviate  the  necessity  of  destroying  from  1,000  to 
100,000  next  year." 

"Efforts  have  been  made  to  check  the  progress  of  tumbleweeds  or, 
at  least,  of  the  Russian  thistle,  by  building  fences.  Thase  efforts  have 
been  successful  only  in  a  very  small  degree,  as  the  weeds  pile  up  and  are 
blown  over  the  tops  of  the  fences,  and  also  the  detached  seeds  are  blown 
through.  In  any  case  the  only  safe  and  thoroughly  effective  method 
is  to  destroy  the  weeds  before  the  seeds  reach  maturity."  (Yearbook, 
1896.) 


14  THE   CANADA    THISTLE. 

* '  The  plant  seems  to  be  particularly  a  railway  weed.  It  has  appeared 
first  along  the  railways  in  sixteen  of  the  twenty-one  States  and  Terri- 
tories in  which  it  has  been  introduced.  In  nearly  all  the  States  where 
it  is  now  found  its  wide  circulation  has  been  chiefly  by  railways,  in 
spite  of  the  fact  that  railway  companies  have  generally  done  more  than 
all  other  parties  to  combat  it."  (Yearbook,  1896.) 


CANADA  THISTLE. 

The  Canada  thistle,  so  called,  is  altogether  a  different  plant  from  the 
Russian  stranger,  and  is  a  true  thistle.  This  pest  is  known  by  various 
local  names,  as  "cursed  thistle,"  "corn  thistle,"  "hard  thistle,"  and 
"creeping  thistle,"  but  by  whatever  name  called  it  is  always  the  same 
costly,  unconquerable  enemy  of  the  farmer.  This  plant,  although 
known  as  the  Canada  thistle,  is  a  native  of  Europe  and  reached  our 
country  by  Newfoundland,  from  which  point  of  entry  it  has  now 
spread  west  to  Nebraska  and  south  beyond  Virginia.  Like  the  great 
pests  of  our  California  farmers,  the  dreaded  morning-glory  and  the 
Johnson-grass,  it  creeps  through  the  soil  by  means  of  root-stocks  and  it 
is  almost,  impossible  to  eradicate  it,  as  every  piece  of  root  left  in  the 
ground  forms  a  new  plant,  and  the  more  it  is  cut  up  the  more  it  thrives. 

The  following  description  of  the  thistle  is  given  by  Prof.  Moses  Craig, 
Botanist  of  the  Oregon  Agricultural  Experiment  Station: 

"This  plant  differs  from  the  common  Bull  thistle,  for  which  it  is 
often  mistaken,  in  its  slenderer,  wingless  stem  and  branches,  in  the  thin, 
narrow  (%  to  %  inch),  curled  and  more  deeply  cut  leaves,  less  rigid 
prickles,  and  smaller  flower  heads  which  are  about  half  an  inch  in 
diameter.  It  is  more  difficult  to  destroy  than  the  common  thistle,  as  it 
is  a  perennial,  spreading  by  long  underground  stems,  which  penetrate 
deeply  into  the  soil,  often  below  the  reach  of  the  plow.  These  rhizomes 
extend  horizontally  in  all  directions,  and  being  furnished  with  buds 
send  branches  to  the  surface,  where  a  tuft  of  leaves  is  first  produced, 
followed  later  by  aerial  stems,  which  bear  flowers  and  seed.  These  die 
down  to  the  ground  every  fall,  but  in  the  spring  the  rhizomes  again  send 
up  numerous  branches,  which  soon  cover  the  ground,  the  plants  spread- 
ing with  surprising  rapidity  from  year  to  year. 

"This  'Cursed  Thistle'  is  also  propagated  by  seeds,  which,  supported 
by  the  downy  pappus,  are  often  carried  long  distances  by  the  wind. 
Like  most  of  our  troublesome  weeds  it  was  introduced  from  Europe 
and  has  now  become  permanently  established  in  this  country.  It  has 
been  reported  from  nine  counties  in  Oregon,  where  fortunately  it  is 
not  abundant. 

"Cnicus  arvensis,  Hoffra.  Fl.  Germ.  IV  180 — Perennial  and  spreading  by  creeping 
root-stalks  a  foot  or  two  high,  corymbosely  branching,  usually  glabrate  and  green; 


THE  SCOTVH'TJH.-  15 

.-tern  and  branches  wingless :  leaves  lanceolate,  pinnatifid  and  toothed,  furnished 
with  abundant  weak  prickles;  heads  loosely  cymose,  less  than  an  inch  high, 
iliu'dous;  in  male  plant  ovate-globular,  and  flowers  (rose-purple)  well  exserted ;  in 
female  oblong-campanulate  and  flowers  less  projecting;  bracts  of  involucre  all 
impressed.  sh"i't,  and  with  very  small  weak  prickly  points;  only  abortive  anthers 
to  the  female  flowers.  Meadows,  pastures,  and  waste  grounds,  from  Newfoundland 
through  the  Northern  and  Middle  Atlantic  States:  a  too  common  weed.  (Nat. 
from  Eu.) 

• '  Frequent  deep  plowing  will,  in  shallow,  dry  soils,  nearly  always 
destroy  the  thistle,  but  in  light,  rich,  moist  soils  this  usually  fails. 
Wherever  a  dense  sod  can  be  formed  seeding  will  be  found  the  easiest 
moans  of  destruction,  though  not  so  rapid  as  plowing,  hoeing,  salting, 
or  burning  where  these  means  are  available.  On  rich  bottom  lands  or 
in  ground  filled  with  stumps,  a  grass  sod  will  be  found  the  best 
destroyer.  If  the  land  is  not  rich  enough  to  form  a  good  sod  manure  it. 

"Mowing  when  the  thistle  is  coming  into  bloom  does  not  destroy  the 
plant,  though  it  checks  its  growth.  The  application  of  kerosene  or  strong 
orine  to  the  roots,  after  cutting  off  the  tops  three  or  four  inches  below 
the  crown  with  a  spade,  is  effective  and  practicable  in  small  patches. 
In  stony  ground  the  scythe,  salt,  and  sheep  will  be  found  good  destroy- 
ing agents.  If  the  thistles  are  in  fence  rows  move  the  fence,  and  plow. 

"One  object  of  thorough  cultivation  is  that  all  weed  seeds  may 
germinate  and  be  destroyed  at  once  and  not  lie  dormant  in  the  ground, 
coming  up  a  few  at  a  time  to  reseed  the  field.  Plowing  and  stirring  the 
soil  when  infested  with  Canada  thistles,  unless  thoroughly  done,  only 
multiplies  them,  so  do  not  permit  any  leaves  or  underground  stems  to 
remain,  but  burn  the  plants  immediately  after  cutting.  The  cultivation 
need  not  be  deep.  If  all  the  thistles  are  kept  cut  off  three  inches  below 
the  surface  the  underground  portions  will  soon  die  of  exhaustion." 


SCOTCH  THISTLE. 

The  Scotch  thistle  (0  nor  pud  um  acanthium),  or  Cotton  thistle,  has  not 
yet  made  its  appearance  as  a  weed  in  California,  and  it  is  not  nearly 
so  much  to  be  feared  as  either  the  Russian  thistle  or  the  Canada  thistle. 
It  is  well,  however,  to  take  precautions  against  its  introduction,  for 
while  it  is  not  a  serious  pest  in  its  native  land,  the  changed  conditions 
of  California  might  also  change  its  character.  It  has  already  obtained 
a  permanent  foothold  in  some  parts  of  the  East,  but  does  not  rank  as 
a  weed  of  the  first  class.  It  is  easily  kept  in  check  by  vigorous  culti- 
vation and  by  cutting  down  the  plants  close  to  the  ground  before 
blossoming. 


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